Unstimulated salivary secretions were collected for 5 min with the patient seated in an upright position, with the head tilted forward . When possible the tongue, cheek and lip movements were limited during the procedure. At the end of the collection period the patient had to expectorate saliva into the test-tube. Stimulated whole saliva samples were collected by asking patients to chew a small block of paraffin wax or chewing gum. All the saliva secreted for 5 min was then collected in the test-tube. Measuring vessels were weighed after each collection using an electronic scales, and salivary flow rate was expressed in ml/min, which is nearly equivalent to g/min (31). A secretion rate < 0.1-0.2 ml/min for unstimulated flow and < 0.5-0.7 ml/min for stimulated flow was considered as an objective sign of hyposalivation.